Yet, ICI therapy is associated with frequent and potentially organ or life-threatening immune-related adverse events (irAEs), generally mimicking autoimmune or inflammatory conditions.4 Rheumatic disorders have been reported in this setting, mainly rheumatoid arthritis, polymyalgia rheumatica and systemic lupus erythematosus.1–3 Vasculitis seems to occur more seldom, with predominantly medium-vessel to large-vessel involvement.5 Here, we report on a patient with eosinophilic granulomatosis with polyangiitis (EGPA, formerly Churg-Strauss syndrome) following treatment with ICI for a stage IV melanoma. ...in the context of asthma, hypereosinophilia, pulmonary infiltrates, arthritis and paranasal sinus abnormalities, the diagnosis of EGPA (formerly Churg-Strauss syndrome) was retained6 and the patient was treated with ICS/LABA and intraarticular corticosteroid injection. Moderate asymptomatic hypereosinophilia has been reported in up to 3% of patients treated with ICI.7 To our knowledge, this is the first case report of a patient with ICI-induced EGPA. Since the patient showed no evidence of genuine vasculitis, one might also classify him as having hypereosinophilic asthma with systemic manifestations.8 The pathophysiological process leading to eosinophilia remains unknown, but the high level of serum IgE strongly suggests Th2-mediated reactive hypereosinophilia induced by ICI.